Precise/designable FinFET resistor structure

ABSTRACT

A resistive material is formed straddling over each semiconductor fin that extends upward from a surface of a substrate. The resistive material is then disconnected by removing the resistive material from atop each semiconductor fin. Remaining resistive material in the form of a U-shaped resistive material liner is present between each semiconductor fin. Contact structures are formed perpendicular to each semiconductor fin and contacting a portion of a first set of the semiconductor fins and a first set of the U-shaped resistive material liners.

BACKGROUND

The present application relates to a semiconductor structure and amethod of forming the same. More particularly, the present applicationrelates to a semiconductor structure including a plurality of U-shapedresistive material liners located between each semiconductor fin that ispresent on a surface of a substrate, and contact structures in contactwith a portion of a first set of the semiconductor fins and with aportion of a first set of the U-shaped resistive material liners. Thepresent application also relates to a method of forming such asemiconductor structure.

A resistor, which is a passive two-terminal electrical component thatimplements electrical resistance as a circuit element, is one of themost common electrical components present in almost every electricaldevice. In electronic circuits, resistors can be used to limit currentflow, to adjust signal levels, bias active elements, and terminatetransition lines.

Front-end-of-the-line (FEOL) resistors are normally created with activematerials (e.g., Si/SiGe), gate materials (e.g., doped polysilicon) ormetals or metal alloys (e.g., tantalum nitride). Different resistivityresistors are usually offered using polysilicon resistors, metalresistors and diffusion resistors. Tuning the resistor value accuratelyto a specific application is highly desired and can be difficult usingprior resistor architecture. There is thus a need for providing aresistor architecture that can be accurately tuned.

SUMMARY

A resistive material is formed straddling over each semiconductor finthat extends upward from a surface of a substrate. The resistivematerial is then disconnected by removing the resistive material fromatop each semiconductor fin. Remaining resistive material in the form ofa U-shaped resistive material liner is present between eachsemiconductor fin. Contact structures are formed perpendicular to eachsemiconductor fin and contacting a portion of a first set of thesemiconductor fins and a first set of the U-shaped resistive materialliners. The resistivity value of the structure can be tuned by any ofthe following: (1) choice of resistive material employed as the U-shapedresistive material liner, (2) the thickness of the U-shaped resistivematerial liner, (3) the number of semiconductor fins and U-shapedresistive material liners contacted, (4) length between contactstructures, and (5) height of each semiconductor fin.

In one aspect of the present application, a semiconductor structure(e.g., a FinFET resistor structure) is provided. In one embodiment ofthe present application, the semiconductor structure includes aplurality of semiconductor fins extending upward from a surface of asubstrate. A U-shaped resistive material liner is located between eachneighboring pair of semiconductor fins. A middle-of-the-line (MOL)dielectric material is located above each U-shaped resistive materialliner and a topmost surface of each semiconductor fin. Contactstructures are located in the MOL dielectric material and contacting aportion of a first set of the semiconductor fins and a portion of afirst set of the U-shaped resistive material liners.

In another aspect of the present application, a method of forming asemiconductor structure (e.g., a FinFET resistor structure) is provided.In one embodiment of the present application, the method includesforming a layer of resistive material straddling over each semiconductorfin of a plurality of semiconductor fins. Next, the layer of resistivematerial is removed from a topmost surface of each semiconductor fin,wherein a U-shaped resistive material liner remains between eachsemiconductor fin of the plurality of semiconductor fins. Contactstructures are then formed perpendicular to each semiconductor fin,wherein each contact structure contacts a portion of a first set of thesemiconductor fins and a portion of a first set of the U-shapedresistive material liners.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross sectional view of an exemplary semiconductor structureincluding a plurality of semiconductor fins extending upward from asurface of a substrate.

FIG. 2 is a cross sectional view of the exemplary semiconductorstructure of FIG. 1 after forming a layer of resistive material on theexposed surface of the substrate and on exposed sidewalls and a topmostsurface of each semiconductor fin.

FIG. 3 is a cross sectional view of the exemplary semiconductorstructure of FIG. 2 after forming a dielectric material on the layer ofresistive material.

FIG. 4 is a cross sectional view of the exemplary semiconductorstructure of FIG. 3 after removing an upper portion of the dielectricmaterial and an upper portion of the layer of resistive material toexpose the topmost surface of each semiconductor fin.

FIG. 5A is a cross sectional view of the exemplary semiconductorstructure of FIG. 4 after removing the remaining portion of thedielectric material to expose each remaining portion of the layer ofresistive material.

FIG. 5B is a top down view of the exemplary semiconductor structure ofFIG. 5A.

FIG. 6 is a top down view of the exemplary semiconductor structure ofFIGS. 5A-5B after forming a middle-of-the-line (MOL) dielectricmaterial.

FIG. 7 is a top down view of the exemplary semiconductor structure ofFIG. 6 after forming contact openings in the MOL dielectric material.

FIG. 8 is a top down view of the exemplary semiconductor structure ofFIG. 7 after forming a contact structure in each contact opening.

DETAILED DESCRIPTION

The present application will now be described in greater detail byreferring to the following discussion and drawings that accompany thepresent application. It is noted that the drawings of the presentapplication are provided for illustrative purposes only and, as such,the drawings are not drawn to scale. It is also noted that like andcorresponding elements are referred to by like reference numerals.

In the following description, numerous specific details are set forth,such as particular structures, components, materials, dimensions,processing steps and techniques, in order to provide an understanding ofthe various embodiments of the present application. However, it will beappreciated by one of ordinary skill in the art that the variousembodiments of the present application may be practiced without thesespecific details. In other instances, well-known structures orprocessing steps have not been described in detail in order to avoidobscuring the present application.

It will be understood that when an element as a layer, region orsubstrate is referred to as being “on” or “over” another element, it canbe directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” or “directly over” another element, there are no interveningelements present. It will also be understood that when an element isreferred to as being “beneath” or “under” another element, it can bedirectly beneath or under the other element, or intervening elements maybe present. In contrast, when an element is referred to as being“directly beneath” or “directly under” another element, there are nointervening elements present.

Referring first to FIG. 1, there is illustrated an exemplarysemiconductor structure including a plurality of semiconductor fins 12extending upward from a surface of a substrate 10. The number ofsemiconductor fins 12 that are located on substrate 10 may vary as longas at least two semiconductor fins 12 are present.

The exemplary semiconductor structure shown in FIG. 1 can be formed byfirst providing a semiconductor substrate. In one embodiment, thesemiconductor substrate may be a bulk semiconductor substrate. The term“bulk” when used in conjunction with the term “semiconductor substrate”denotes a substrate that is entirely composed of at least onesemiconductor material having semiconducting properties; no insulatormaterials and/or conductive materials are present in a bulksemiconductor substrate. In such an embodiment and after performing apatterning process (to be defined in greater detail below), an upperportion of the bulk semiconductor substrate constitutes thesemiconductor fins 12, while a remaining portion of the bulksemiconductor substrate constitutes the substrate 10.

Examples of semiconductor materials that may provide at least a portionof the bulk semiconductor substrate include silicon (Si), germanium(Ge), silicon germanium alloys (SiGe), silicon carbide (SiC), III-Vcompound semiconductors or II-VI compound semiconductors. III-V compoundsemiconductors are materials that include at least one element fromGroup III of the Periodic Table of Elements and at least one elementfrom Group V of the Periodic Table of Elements. II-VI compoundsemiconductors are materials that include at least one element fromGroup II of the Periodic Table of Elements and at least one element fromGroup VI of the Periodic Table of Elements. In one example, the bulksemiconductor substrate may be entirely composed of silicon. In anotherexample, the bulk semiconductor substrate may include a multilayeredsemiconductor material stack of, and in any order, Si and a silicongermanium alloy.

The semiconductor material that provides the bulk semiconductorsubstrate may be a single crystalline semiconductor material. Thesemiconductor material that provides the bulk semiconductor substratemay have any of the well known crystal orientations. For example, thecrystal orientation of the bulk semiconductor substrate may be {100},{110}, or {111}. Other crystallographic orientations besides thosespecifically mentioned can also be used in the present application.

In another embodiment, the semiconductor substrate that may be used is asemiconductor-on-insulator (SOI) substrate. The SOI substrate mayinclude a handle substrate, an insulator layer and a topmostsemiconductor material layer. In some embodiments, the handle substratemay be omitted. When an SOI substrate is employed, the topmostsemiconductor material layer of the SOI substrate is patterned into thesemiconductor fins 12 shown in FIG. 1, while substrate 10 includes theinsulator layer and, if present, the handle substrate of the SOIsubstrate.

The handle substrate of the SOI substrate may include a semiconductormaterial or a non-semiconductor material such as, for example, adielectric material and/or a conductive material. When the handlesubstrate is a semiconductor material, the semiconductor material thatprovides the handle substrate may include one of the semiconductormaterials mentioned above for the bulk semiconductor substrate. Thesemiconductor material that can provide the handle substrate can be asingle crystalline semiconductor material and it can have any of thecrystal orientations mentioned above for the semiconductor material thatprovides the bulk semiconductor substrate.

The insulator layer of the SOI substrate may be a crystalline ornon-crystalline dielectric material. In one embodiment, the insulatorlayer of the SOI substrate is a dielectric oxide such as, for example,silicon dioxide. In another embodiment, the insulator layer of the SOIsubstrate is a dielectric nitride such as, for example, silicon nitrideor boron nitride. In yet another embodiment, the insulator layer of theSOI substrate may include a multilayered stack of different dielectricmaterials. In one example, the insulator layer may include amultilayered stack of, and in any order, silicon dioxide and boronnitride.

The topmost semiconductor layer of the SOI substrate may include one ofthe semiconductor materials mentioned above for the bulk semiconductorsubstrate. The semiconductor material that can provide the topmostsemiconductor layer of the SOI substrate can be a single crystallinesemiconductor material and it can have any of the crystal orientationsmentioned above for the semiconductor material that provides the bulksemiconductor substrate. The semiconductor material that provides thetopmost semiconductor layer of the SOI substrate may be the same as, ordifferent from, a semiconductor material that provides the handlesubstrate.

After providing the semiconductor substrate (i.e., bulk or SOI), thesemiconductor substrate can patterned to provide a plurality ofsemiconductor fins 12 extending upward from substrate 10. Eachsemiconductor fin 12 constitutes either a remaining upper portion of abulk semiconductor substrate or the topmost semiconductor layer of anSOI substrate, and substrate 10 constitutes either a remaining portionof the bulk semiconductor substrate or at least the insulator layer ofthe SOI substrate. In some embodiments, no material interface existsbetween the semiconductor fins 12 and the substrate 10. In otherembodiments, a material interface exists between the semiconductor fins12 and the substrate 10.

In one embodiment, patterning may include lithography and etching. Thelithographic process includes forming a photoresist (not shown) atop amaterial or material stack to be patterned, exposing the photoresist toa desired pattern of radiation and developing the exposed photoresistutilizing a conventional resist developer. The photoresist may be apositive-tone photoresist, a negative-tone photoresist or a hybrid-tonephotoresist. The photoresist may be formed utilizing a depositionprocess such as, for example, spin-on coating. The etching processincludes a dry etching process (such as, for example, reactive ionetching, ion beam etching, plasma etching or laser ablation), and/or awet chemical etching process. Typically, reactive ion etching is used inproviding the semiconductor fins 12 shown in FIG. 1 of the presentapplication.

In another embodiment, patterning may include a sidewall image transfer(SIT) process. The SIT process includes forming a mandrel material layer(not shown) atop the material or material layers that are to bepatterned. The mandrel material layer (not shown) can include anymaterial (semiconductor, dielectric or conductive) that can beselectively removed from the structure during a subsequently performedetching process. In one embodiment, the mandrel material layer (notshown) may be composed of amorphous silicon or polysilicon. In anotherembodiment, the mandrel material layer (not shown) may be composed of ametal such as, for example, Al, W, or Cu. The mandrel material layer(not shown) can be formed, for example, by chemical vapor deposition orplasma enhanced chemical vapor deposition. Following deposition of themandrel material layer (not shown), the mandrel material layer (notshown) can be patterned by lithography and etching to form a pluralityof mandrel structures (also not shown) on the topmost surface of thestructure.

The SIT process continues by forming a spacer (not shown) on eachsidewall of each mandrel structure. The spacer can be formed bydeposition of a spacer material and then etching the deposited spacermaterial. The spacer material may comprise any material having an etchselectivity that differs from the mandrel material. Examples ofdeposition processes that can be used in providing the spacer materialinclude, for example, chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition (PECVD), or atomic layer deposition (ALD).Examples of etching that be used in providing the spacers include anyetching process such as, for example, reactive ion etching.

After formation of the spacers, the SIT process continues by removingeach mandrel structure. Each mandrel structure can be removed by anetching process that is selective for removing the mandrel material.Following the mandrel structure removal, the SIT process continues bytransferring the pattern provided by the spacers into the underlyingmaterial or material layers. The pattern transfer may be achieved byutilizing at least one etching process. Examples of etching processesthat can used to transfer the pattern may include dry etching (i.e.,reactive ion etching, plasma etching, and ion beam etching or laserablation) and/or a chemical wet etch process. In one example, the etchprocess used to transfer the pattern may include one or more reactiveion etching steps. Upon completion of the pattern transfer, the SITprocess concludes by removing the spacers from the structure. Eachspacer may be removed by etching or a planarization process.

As used herein, a “semiconductor fin” refers to a semiconductor materialthat includes a pair of vertical sidewalls that are parallel to eachother. As used herein, a surface is “vertical” if there exists avertical plane from which the surface does not deviate by more thanthree times the root mean square roughness of the surface. In oneembodiment of the present application, each semiconductor fin 12 has aheight from 20 nm to 200 nm, and a width from 5 nm to 30 nm. Otherheights and/or widths that are lesser than, or greater than, the rangesmentioned herein can also be used in the present application. Eachsemiconductor fin 12 is spaced apart from its nearest neighboringsemiconductor fin 12 by a pitch of from 20 nm to 100 nm. Also, eachsemiconductor fin 12 is oriented parallel to each other. A gap 13 ispresent between each neighboring pairs of semiconductor fins 12.

Referring now to FIG. 2, there is illustrated the exemplarysemiconductor structure of FIG. 1 after forming a layer of resistivematerial 14L on the exposed surface of the substrate 10 and on exposedsidewalls and a topmost surface of each semiconductor fin 12. The layerof resistive material 14L is a continuous (without and breaks and/orvoids) layer that straddles over each semiconductor fin 12. By“straddles over” it is meant that a material (such as, for example, thelayer of resistive material 14L) is present on sidewalls and a topmostsurface of another material (such as for example, the semiconductor fin12).

The layer of resistive material 14L may include a metal or metal alloysuch as, for example, titanium nitride (TiN), titanium (Ti), tantalumnitride (TaN), tantalum (Ta), tungsten nitride (WN) or tungsten (W). Themetal or metal alloy that provides the layer of resistive material 14Ldetermines, at least in part, the resistivity of the resistor of thepresent application. The layer of resistive material 14L may be formedutilizing a deposition process such as, for example, chemical vapordeposition (CVD), plasma enhanced chemical vapor deposition (PECVD)physical vapor deposition (PVD) or atomic layer deposition (ALD).

The layer of resistive material 14L may have a thickness from 10 nm to100 nm. Other thicknesses that are lesser than, or greater than, theaforementioned thickness range may also be used as the thickness of thelayer of resistive material 14L as long as the thickness of the layer ofresistive material 14L does not fill in the entirety of gap 13. Thethickness of the layer of resistive material 14L determines, at least inpart, the resistivity of the resistor of the present application.

In some embodiments, the layer of resistive material 14L is a conformallayer (i.e., a material whose vertical thickness above a horizontalsurface of an underlying material is the same as a lateral thicknessalong a sidewall surface of laterally adjacent material). In yet anotherembodiment, the layer of resistive material 14L is a non-conformallayer. In such an embodiment, the vertical thickness of the layer ofresistive material 14L above a horizontal surface of an underlyingmaterial may be greater than the lateral thickness of the layer ofresistive material 14L along the sidewalls of a laterally adjacentmaterial.

Referring now to FIG. 3, there is illustrated the exemplarysemiconductor structure of FIG. 2 after forming a dielectric material 16on the layer of resistive material 14L. The dielectric material 16 thatcan be employed may include a middle-of-the line (MOL) dielectricmaterial.

The dielectric material 16 covers the substrate 10 and the entirety ofthe layer of resistive material 14L. The dielectric material 16 may becomposed of, for example, silicon dioxide, undoped silicate glass (USG),fluorosilicate glass (FSG), borophosphosilicate glass (BPSG), a spin-onlow-k dielectric layer, a chemical vapor deposition (CVD) low-kdielectric layer or any combination thereof. The term “low-k” as usedthroughout the present application denotes a dielectric material thathas a dielectric constant of less than silicon dioxide. In anotherembodiment, a self-planarizing material such as a spin-on glass (SOG) ora spin-on low-k dielectric material such as SiLK™ can be used as thedielectric material 16. The use of a self-planarizing dielectricmaterial as dielectric material 16 may avoid the need to perform asubsequent planarizing step.

In one embodiment, the dielectric material 16 can be formed utilizing adeposition process including, for example, chemical vapor deposition(CVD), plasma enhanced chemical vapor deposition (PECVD), evaporation orspin-on coating. In some embodiments, a planarization process or an etchback process follows the deposition of the dielectric material 16. Thethickness of the dielectric material 16 that can be employed in thepresent application may vary depending on the type of material employedas well as the method that was employed in forming the same. In oneembodiment, the dielectric material 16 has a thickness from 80 nm to 500nm. Other thicknesses that are greater or lesser than the range providedabove can also be used for the dielectric material 16.

Referring now to FIG. 4, there is illustrated the exemplarysemiconductor structure of FIG. 3 after removing an upper portion of thedielectric material 16 and an upper portion of the layer of resistivematerial 14L to expose the topmost surface of each semiconductor fin 12.The removal of the upper portion of the dielectric material 16 and theupper portion of the layer of resistive material 14L may be performedutilizing a planarization process such as, for example, chemicalmechanical polishing and/or grinding. After removing the upper portionof the dielectric material 16 and the upper portion of the layer ofresistive material 14L, a portion of the dielectric material 16 and aportion of the layer of resistive material 14L remain in the gap 13.

Each remaining portion of the dielectric material 16 is referred toherein as a dielectric material portion 16P and each remaining portionof the layer of resistive material 14L may be referred to herein as aU-shaped resistive material liner 14. By “U-shaped” it is meant amaterial that has a horizontal portion (labeled as element 14A) and twovertical portions (labeled as element 14B) that extend upwards from eachend of the horizontal portion 14A. The vertical portions 14B of eachU-shaped resistive material liner 14 are present along a sidewall of oneof the semiconductor fins 12, while the horizontal portion 14A of theU-shaped resistive material liner 14 is present on a topmost surface ofthe substrate 10. As is shown, each U-shaped resistive material liner 14has a topmost that is coplanar with a topmost surface of eachsemiconductor fin 12 as well the topmost surface of each dielectricmaterial portion 16P. At this point of the present application, theU-shaped resistive material liners 14 are disconnected from each other.

Referring now to FIGS. 5A-5B, there are shown various views of theexemplary semiconductor structure of FIG. 4 after removing the remainingportion of the dielectric material (i.e., dielectric material portions16P) to expose each remaining portion of the layer of resistive material(i.e., the U-shaped resistive material 14). In some embodiments (and asshown), each dielectric material portion 16P is entirely removed. Insuch an embodiment, the entirety of each U-shaped restive material liner14 is exposed. In another embodiment (not shown), each dielectricmaterial portion 16P is partially removed. In such an embodiment, theupper portion of each U-shaped restive material liner 14 is exposed. Inyet other embodiments, this step of the present application may beomitted.

The complete or partial removal of the dielectric material portions 16Pmay be performed utilizing an anisotropic etching process that isselective in removing the dielectric material that provides eachdielectric material portion 16P relative to the resistive material thatprovides the U-shaped resistive material liners 14 and the semiconductormaterial that provides the semiconductor fins 12. In one example, andwhen an oxide is employed as the dielectric material that provides eachdielectric material portion 16P, each dielectric material portion 16Pmay be removed (entirely or partially) utilizing an anisotropic etchingprocess in which hydrofluoric acid (HF) or a mixture of ammoniumfluoride and hydrofluoric acid (so called buffer oxide etchant) can beemployed as a chemical etchant. In another example, and when an oxide isemployed as the dielectric material that provides each dielectricmaterial portion 16P, each dielectric material portion 16P may beremoved (entirely or partially) utilizing an anisotropic etching processin which a plasma of CF₄, SF₆ of NF₃ can be employed as an etchant.

Referring now to FIG. 6, there is illustrated the exemplarysemiconductor structure of FIGS. 5A-5B after forming amiddle-of-the-line (MOL) dielectric material 18. The MOL dielectricmaterial 18 may include one of the dielectric materials mentioned abovefor dielectric material 16. In some embodiments, the dielectric materialthat provides the MOL dielectric material 18 may be the same as thedielectric material that provides dielectric material 16. In otherembodiments, the dielectric material that provides the MOL dielectricmaterial 18 may be a different dielectric material than dielectricmaterial 16. The MOL dielectric material 18 may be formed utilizing oneof the techniques mentioned above in forming dielectric material 16. TheMOL dielectric material 18 may have a thickness within the rangementioned above for dielectric material 16.

In some embodiments and when the dielectric material portions 16P arecompletely removed, the MOL dielectric material 18 is formed within eachgap 13 and directly on each U-shaped resistive material liner 14. Insuch an embodiment, the MOL dielectric material 18 is also formeddirectly on a topmost surface of each semiconductor fin 12.

In other embodiments and when the dielectric material portions 16P arepartially removed, the MOL dielectric material 18 is formed within eachgap 13 and directly on a remaining segment of each dielectric materialportion 16P and directly on any exposed portion of each U-shapedresistive material liner 14. In such an embodiment, the MOL dielectricmaterial 18 is also formed directly on a topmost surface of eachsemiconductor fin 12.

In yet further embodiments and when the dielectric material portions 16Pare not removed, the MOL dielectric material 18 is formed directly onthe topmost surfaces of each dielectric material portion 16P and eachsemiconductor fin 12.

Referring now to FIG. 7, there is illustrated the exemplarysemiconductor structure of FIG. 6 after forming contact openings 20L,20R in the MOL dielectric material 18. Each contact opening 20L, 20R isspaced apart from one another. Although the present applicationillustrates the formation of two contact openings 20L, 20R, the presentapplication is not limited to the formation of two contact openings.Instead, more than two contact openings can be formed as desired. Thenumber of contact openings that are formed can also, in part, determinethe resistivity of the resistor of the present application.

As is shown, each contact opening exposes a portion of a first set ofthe semiconductor fins 12 and a portion of a first set of the U-shapedresistive material liners 14 (including the vertical portions 14B andthe horizontal portions 14A of a particular U-shaped resistive materialliner 14). In the illustrated embodiment, contact opening 20L exposes afirst portion of a first set of the semiconductor fins 12 and a firstportion of a first set of the U-shaped resistive material liners 14,while the second contact opening exposes a second portion of the firstset of the semiconductor fins 12 and a second portion of the first setof the U-shaped resistive material liners 14. The number ofsemiconductor fins 12 and U-shaped resistive material liners 14 that areexposed by the contact openings may vary and is not limited to two as isshown by way of one example in FIG. 7. Each contact opening 20R, 20L canbe formed utilizing conventional techniques such as, for example,lithography and etching.

Referring now to FIG. 8, there is illustrated the exemplarysemiconductor structure of FIG. 7 after forming a contact structure 22L,22R in each contact opening 20L, 20R; the contact structures may also bereferred to as metal contact structures. Each contact structure 22L, 22Ris spaced apart from each other by a specific distance. As evident bycomparing FIGS. 7 and 8 to each other, each contact structure 22L, 22Ris formed perpendicular to the semiconductor fins 12. Although thepresent application illustrates the formation of two contact structures22L, 22R within two contact openings 20L, 20R, the present applicationis not limited to the formation of two contact structures. Instead, morethan two contact structures can be formed as desired. The length, i.e.,distance, between each contact structure 22L, 22R may also, in part,determine the resistivity of the resistor of the present application.

Each contact structure 22L, 22R may be composed of a metal or metalalloy having a lower resistivity than the metal or metal alloy thatprovides each U-shaped resistive material liner 14. Stated in oppositeterms, the metal or metal alloy that provides each U-shaped resistivematerial liner 14 has a higher resistivity than the metal or metal alloythat provides each contact structure 22L, 22R. Examples of metals ormetal alloys that can be employed as the contact structure 22L, 22Rinclude, but are not to, tungsten (W), cobalt (Co), aluminum (Al),copper (Cu), or an aluminum-copper (Al—Cu) alloy. Each contact structure22L, 22R may be formed by deposition of a contact metal or metal alloy,followed by a planarization process such as, for example, chemicalmechanical polishing. Each contact structure 22L, 22R has a topmostsurface that is coplanar with a topmost surface of the MOL dielectricmaterial 18.

As is shown, each contact 22L, 22R structure lies perpendicular to eachsemiconductor fin 12. Also, each contact structure 22L, 22R contacts theexposed portion of the first set of the U-shaped resistive materialliners 14 (notably each contact structure contacts the vertical portionsand horizontal portions of each of the exposed U-shaped resistivematerial liners) and the exposed portion of the first set of thesemiconductor fins 12. In the illustrated embodiment, the contactstructure 22L contacts an exposed first portion of the first set of thesemiconductor fins 12 and an exposed first portion of the first set ofthe U-shaped resistive material liners 14, while contact structure 22Rcontacts the exposed second portion of the first set of thesemiconductor fins 12 and the exposed second portion of the first set ofthe U-shaped resistive material liners 14.

It is noted that the desired resistivity value of the structure can betuned by any of the following: (1) choice of resistive material employedas the U-shaped resistive material liner 14, (2) the thickness of theU-shaped resistive material liner 14, (3) the number of semiconductorfins 12 and U-shaped resistive material liners 14 exposed by the contactopenings 20A, 20B, (4) length between contact structures 22L, 22R, and(5) height of each semiconductor fin 12.

While the present application has been particularly shown and describedwith respect to preferred embodiments thereof, it will be understood bythose skilled in the art that the foregoing and other changes in formsand details may be made without departing from the spirit and scope ofthe present application. It is therefore intended that the presentapplication not be limited to the exact forms and details described andillustrated, but fall within the scope of the appended claims.

What is claimed is:
 1. A method of forming a resistor structure, themethod comprising: forming a layer of resistive material straddlingover, and in direct contact with, each semiconductor fin of a pluralityof semiconductor fins, wherein said layer of resistive material isselected from the group consisting of a metal and a metal nitride;removing the layer of resistive material from a topmost surface of eachsemiconductor fin of the plurality of semiconductor fins, wherein aU-shaped resistive material liner remains between each neighboring pairof semiconductor fins of the plurality of semiconductor fins; andforming spaced apart contact structures that are oriented perpendicularto each semiconductor fin of the plurality of semiconductor fins,wherein each of the spaced apart contact structures contacts a differentportion of one of the neighboring pairs of semiconductor fins and theU-shaped resistive material liner that is located between the one of theneighboring pairs of semiconductor fins, and each of the spaced apartcontact structures is in direct physical contact with a topmost surfaceof a vertical portion of the U-shaped resistive material liner that islocated between the one of the neighboring pairs of semiconductor fins.2. The method of claim 1, wherein the topmost surface of each of theU-shaped resistive material liners is coplanar with the topmost surfaceof each semiconductor fin of the plurality of semiconductor fins.
 3. Themethod of claim 1, wherein the removing the layer of resistive materialcomprises: forming a dielectric material over the layer of resistivematerial and over each semiconductor fin of the plurality ofsemiconductor fins; and removing an upper portion of the dielectricmaterial and an upper portion of the layer of resistive material that ispresent on the topmost surface of each semiconductor fin of theplurality of semiconductor fins utilizing a planarization process. 4.The method of claim 3, further comprising removing an entirety of aremaining portion of the dielectric material that is present on each ofthe U-shaped resistive material liners.
 5. The method of claim 3,further comprising partially removing a remaining portion of thedielectric material.
 6. The method of claim 1, wherein the forming thespaced apart contact structures comprises: forming a middle-of-the-linedielectric material over each of the U-shaped resistive material linersand over each semiconductor fin of the plurality of semiconductor fins;forming contact openings that expose the different portions of the oneof the neighboring pairs of semiconductor fins and the U-shapedresistive material liner that is located between the one of theneighboring pairs of semiconductor fins; and forming a second metal or ametal alloy in the contact openings.
 7. The method of claim 6, whereinthe second metal or metal alloy that provides each of the spaced apartcontact structures has a lower resistivity than the metal or metalnitride that provides each of the U-shaped resistive material liners. 8.The method of claim 7, wherein the metal or metal nitride is titaniumnitride (TiN), titanium (Ti), tantalum nitride (TaN), tantalum (Ta),tungsten nitride (WN) or tungsten (W).
 9. The method of claim 8, whereinthe second metal or metal alloy is tungsten (W), cobalt (Co), aluminum(Al), copper (Cu), or an aluminum-copper (Al—Cu) alloy.
 10. The methodof claim 1, wherein the resistor structure has a resistivity value thatcan tuned by at least one of the following: the choice of the metal ordie metal nitride used as the layer of resistive material, a thicknessof the layer of resistive material, a number of the neighboring pairs ofsemiconductor fins, a length between the spaced apart contactstructures, and a height of each semiconductor fin of the plurality ofsemiconductor fins.
 11. A method of forming a resistor structure, themethod comprising: forming a layer of resistive material straddlingover, and in direct contact with, each semiconductor fin of a pluralityof semiconductor fins, wherein said layer of resistive material isselected from the group consisting of a metal and a metal nitride;removing the layer of resistive material from a topmost surface of eachsemiconductor fin of the plurality of semiconductor fins, wherein aU-shaped resistive material liner remains between each neighboring pairof semiconductor fins of the plurality of semiconductor fins; andforming spaced apart contact structures that are oriented perpendicularto each semiconductor fin of the plurality of semiconductor fins,wherein each of the spaced apart contact structures contacts a differentportion of one of the neighboring pairs of semiconductor fins and theU-shaped resistive material liner that is located between the one of theneighboring pairs of semiconductor fins, and wherein each of the spacedapart contact structures is in direct physical contact with a horizontalsurface of the U-shaped resistive material liner that is located betweenthe one of the neighboring pairs of semiconductor fins.